Adaptive Reuse of Vernacular Architecture for Conservation in Indonesia: Case Study of South Nias Village, Bawömataluo Conservation Project

Bawömataluo village, which is located in Nias Island, Indonesia, is among the most important National Cultural Properties. The village has the highest number of surviving traditional houses in one village in Indonesia (53% left – Fanitra Pedi A., 2017, p. 64). The architecture is considered to be the finest artistic masterpiece in Indonesia. The change of agriculture type in the 20th century and vast improvement of infrastructure in the 21st century cause poverty and bring difficulties in sustaining the cultural property. Villagers modify their houses by replacing some of the building materials with the ones that are more economical in price, but this contributes to the destruction of the original structure. Most Nias villagers still want to stay in their traditional houses. But, due to the maintenance funding problem and introduction to healthy houses in the 20th century, some materials were changed into industrial materials and some parts were damaged. There is an initiative to use traditional house/ omo hada as a homestay program which allows villagers to have a close contact with local and international tourists and earn more income. This research observed 30 omo hada and took two samples for a deeper space understanding. This paper tries to investigate activities in the two samples of omo hada with and without homestay activities. The investigation finds out that tawolo (communal space that is located at the front of the house) is a frequently used space which occupies 40% area of the second floor and föröma (private space that is located at the back of the house) is the least used space with 60% area of the second floor which is suitable for adaptive reuse in omo hada .


Introduction
Indonesia has 14,000 islands and 300 ethnic groups that live in it with diverse native culture. The country has rich forest resources and natural resources. Each ethnic group lives in a specific region and has its own culture and tradition. In addition, each ethnic group profoundly expresses the characteristics of its demographical, geographical and ecological conditions. The wooden buildings, which are unique and diverse from one to another ethnic group found in Indonesia, showed the richness of the culture. In the post-colonial era, industrialization came and the healthful house program from the government in the 20th century caused the replacement of wooden structures and reinforced concrete and brick buildings (Semiarto,p. 606). Aside from having many earthquakes, Indonesia has tropical seasons (e.g., tropical rainforest, savanna and monsoon) that could cause extensive biological damage from termite and insect pests. These reasons make conservation difficult. Other than the vast improvement of infrastructure in the 21 st century, the deforestation and change of agriculture type bring poverty and difficulty for the group to maintain their omo hada.
It is written on the Decision Letter No. 186/M/2017 of 6 July 2017 that Bawömataluo village becomes a National Cultural Property. It is considered as the first living monument in Indonesia National Heritage Property. Bawömataluo village has the most authentic traditional house left compared to other traditional villages in Indonesia. Its villagers also have authentic carpenter and carving skills. This unique identity attracts some local and foreign tourists to visit Bawömataluo village. Since the village is located approximately 22 km from the city centre, many local and international tourists must travel all the way from the accommodation in the city centre to ach.ccsenet.org Asian Culture and History Vol. 15, No. 1;2023 Bawömataluo village. Some villagers then have an initiative to accept guests in a homestay program. This paper tries to observe the space and activity inside omo hada with and without homestay activities to understand which area is possible to be modified and which area needs to be preserved according to the original function.

Figure 1. Map of Indonesia and the traditional villages in South Nias
Bawömataluo village, which is located in Nias island, is a great example of a living heritage in Indonesia because the village shows the structural genius of its wooden architecture and stone composition in village planning. The traditional wooden housing in Nias Island is considered as the most impressive structure ever produced in Indonesia (Feldman, 1977). The village covers an area of five hectares with an altitude of 270 meters above the sea. Bawömataluo is a new village that is formed after the first traditional village in South Nias, Orahili, which was burnt by the Dutch military. Nias traditional houses use ironwood piles with large diameter to form the substructure of the house. Omo hada, which means rumah adat (traditional house), uses special diagonal and vertical V-shaped pair piles called driwa, which added resistance to earthquake stresses as well as stability to the structure as a whole. The house has many details in the wood joints and uses two kinds of hardwoods originating from Nias Island called manawadanö and berua. There are three main components of the traditional house. The first component is the substructure which has four wide ehomo (pillar), seven deeps and six bays. The ehomo works as a foundation pillar and it is put above the square stone called batu gehomo. There are also 14 transverse driwa and 12 longitudinal driwa (V-shaped wooden braces). The second structure is the main structure where there is a front room (tawolo) and a rear private room (föröma). Originally, the main structure was the only space that was used by the villagers for sleeping, eating, conducting traditional ceremonies, chatting, and relaxing. But recently, the population grew and more space is necessary. The front room (tawolo) serves as a public room for guests, whereas the föröma is a private family quarter. Finally, the top structure is superstructure and refers to the roof structure. The roof scale is two thirds of the total height. The roof structure such as braces is placed in the span of direction. The traditional ach.ccsenet.org Asian Culture and History Vol. 15, No. 1;2023 roof is shingled with sago palm leaves.
This village was chosen as a special reference for this research because it indicated outstanding historical and great cultural values. Until 2022, 52% of the houses are still traditional and the three main parts still remain although some functions have been modified and developed. Based on the research in 2022, there are 256 houses in the village, 136 of which were built using the traditional construction method. The structural genius of Bawömataluo's traditional architecture is still preserved and some local carpenters are still familiar with the traditional construction technique. The tangible cultural property is still preserved but some traditional activities inside the village have changed due to the influence of modern era. Bawömataluo village, which is located in Nias Island, Indonesia, is among the most important National Cultural Properties. However, there are only 52% of traditional houses left in Bawömataluo village right now and the number might be decreasing in the following year. It is an urgent issue because these wooden cultural properties might disappear soon.

Literature Study
The writer conducted literature studies about the preservation of Japanese traditional wooden architecture and the Japanese system of heritage conservation. Literature about conservation of Indonesian wooden cultural properties is also studied to understand the problems and challenges. Studies from previous related research will be useful to enrich this research. The past studies include research from Jerome Feldman (a professor in Hawai'i Pacific University), Alain Viaro and Pastor Josef (missionaries who work on Pusaka Nias Museum) and some Japanese experts who had done research about Bawömataluo village in Nias island.

On-Site and Offline Survey and Interview in Bawömataluo Village, South Nias Island
During the master's degree program (2016)(2017)(2018), the writer recorded the architectural drawing of omo hada and some of the modification projects held by the village. And during the doctoral degree that began in 2022, the writer contacted Bawömataluo villagers online to record the new modification on traditional house/omo hada. Finally, the author visited Bawomataluo village in 2016-2018 to interview some villagers and met them during the pandemic in 2022 through online platform communication such as Whats app application and zoom meetings.

Data Analysis
Data analysis was conducted to identify the house's typology, area size of tawolo and föröma, as well as activities inside omo hada with and without homestay guests.

South Nias Settlement and Bawömataluo Village
During The village has an important word that represents the concept of their living heritage. The word is called banua. Through this word, South Nias people hold an important meaning for the culture and the development of their residential area. The banua means the world of living humans, its culture, domesticated animals, and harvested plants while anything outside the banua is the underworld of the dead, wild animals, and undomesticated plants.
The banua concept appears on the traditional house called omo hada while the outside banua appears in the form of sculpture in the village street's megalithic stones. A familiar term that is used is raya, but this actually means sunrise and it is located in the eastern part. Meanwhile, löu means sunset and is located in the western area. The ach.ccsenet.org Asian Culture and History Vol. 15, No. 1;2023 words raya and löu are used to name the streets in Bawömataluo village where their location is exactly at the directions of sunrise and sunset. This concept was mentioned by a professor from Hawai'i Pacific University named Jerome Feldman in his dissertation.

Survey Activity at Bawömataluo Village
The on-site survey in Bawömataluo Village was held twice in September 2016 and September 2017 while the online survey was conducted one time in June 2022. The survey is expected to record the current housing type, current condition, new construction, and modification activities of omo hada. The on-site survey is located only in the uphill area where the most traditional houses omo hada are still used.
The survey recorded that there are three types of houses in Bawömataluo Village. Type A (traditional and original) is where the traditional omo hada still has full components of V-brace column, sago palm roof, and horizontal lattice ventilation (zarazara). Type B (traditional with various modifications especially in faç ade) shows the modified traditional omo hada, with modification on the foundation part that is done by adding new wooden or concrete material and changing the roof material into metal zinc. And the last one is type C (different style of housing). Type C is a different style of housing. Some houses are built with concrete materials while some are still using wooden materials, but the shape is completely different from omo hada.
From the map containing the number and locations of different housing types above, it is clear that most traditional preserved houses are located in the centre of settlement. The raya area has the most traditional houses among all aisles in Bawömataluo Village. There are three type A houses and 52 type B houses in the raya area.

Result: Adaptive Reuse of Omo Hada -Vernacular Architecture in Indonesia
The on-site survey consists of the questionnaire and measurement of selected omo hada in Bawömataluo Village located at the uphill area. This survey is one of the ways to understand in detail about the activities, circulation, user behavior and spaces inside omo hada. The questionnaire was carried out in 30 traditional houses (10 houses in löu aisle, two houses in bagoa aisle, nine houses in raya aisle, and nine houses in halam ba'a aisle). The criteria of the chosen 30 houses are: 1) Type A (traditional house) and type B (traditional modified house), 2) Houses with a maximum of 10 inhabitants. The interview includes seven questions for the villagers which are the year the house was built, the property owner of the house, number of people staying in omo hada with age information, activities in omo hada, the most and least frequently used space in omo hada (with detailed user and space location), homestay experience in their omo hada, and detailed information about guests' purpose of homestay in omo hada.
Each question of the questionnaire is analyzed and the results with explanations from each question are as follows: 30 samples of omo hada were taken to understand about the ownership, homestay experiences, as well as activities in tawolo and föröma. Among 30 houses, there were nine houses that have ever experienced homestay.   The data below are the two samples of omo hada taken to understand more about the activity inside the house and the alteration of space when they receive homestay activities.

Sample 1
Sample 1 is an omo hada number 144 which is located in the raya area. There is no information about the year built and renovation work. There are five inhabitants in this omo hada which is the husband and wife with two male children and a grandmother. This house is built on inherited land. This house has had a homestay experience and received guests from Spain, Jakarta and Nias. The purposes of the guests are holiday and research activity.

Sample 2
Sample 2 is an omo hada number 19 which is located in the löu area. The house was built in 1948 with no record of renovation work. There are five inhabitants in this omo hada which are the husband and wife with three children. This house is built on inherited land. This house has had homestay experiences and received guests from Germany, Australia, Japan, USA, China, France, Netherland, and Yogyakarta. The purpose of the guests are holiday and research activity.  Table 6. Area used in Sample 2 omo hada (with and without homestay activities) Table 7. Comparison of layout and house activities in omo hada Sample 1 and Sample 2 The site survey shows that tawolo (front area) is the most frequently used space while föröma (back of the house where there are private rooms) is the least used. The villagers also put as tawolo the most favourite space in omo hada. It leads to the idea that the tawolo can be used as a semi-public area for house owners and guests. Tawolo ach.ccsenet.org Asian Culture and History Vol. 15, No. 1;2023 occupies 40% space of the second floor but sometimes if the number of guests is too many, they also use half of tawolo for the sleeping space. The föröma can be used as a bedroom for house owners and guests because the space is wide, and they rarely use this area in daylight. The proportion of föröma is around 60% of the total area of the second floor and guests usually use 20% of föröma.
Furthermore, the floor plan recorded from Bawomataluo villages shows that the villagers modify the föröma instead of the tawolo area. It means that the föröma area is possible to be modified for a homestay area with some adjustments without disturbing the privacy of the house owner and the guest. In the Sample 2 case, föröma is flexible except for the kolukolu area. The house owner never allows this place for the guest because it is always used by the oldest member of the family. In ancient area, kolukolu is a private place and usually a space for newlywed couple.
There are two possible accesses from the original omo hada system which is from the side of tawolo and from the arönoma or the ground floor area. Through the ground floor, arönoma, people can directly access new additional space so this access will be suitable for the house owner. Meanwhile, the original access from the side of the omo hada is suitable for the guest.

Conclusion
There are some problems related to preservation in Indonesia's cultural heritage such as less awareness of the heritage cultural property because of the vast improvements of infrastructure in the 21st century, introduction to healthy houses using industrial materials in 20 th century, introduction to a new religion which changes the way of life, and changes in agriculture type into commercial agriculture. It results in the minimum discussion about Indonesia's living heritage and the lack of experts. The economic disparity between the central region and other small islands also creates a poverty problem which brings difficulty in sustaining the native culture.
Through the literature survey about Bawömataluo Village in the 1860 era and on-site survey from 2017 until 2022, it is understood that the living space of Nias people in omo hada has evolved and transformed due to modern space necessity and financial ability. Some villagers decide to open their own businesses such as grocery shops inside the village in order to provide modern necessities such as soap, toothpaste, detergent, book, stationery, etc. They started to modify the ground area of the house called arönoma for the grocery shop, wood carving shop and photocopy service area. Other than retail space, villagers also start to accept guests to stay with them during the visit.
Bawömataluo village has become Indonesia's National Cultural Property since July 2017. The reuse of cultural property should be considered carefully by understanding the history of the traditional house, local culture, as well as villagers' behaviour and understanding the modern living necessities. To reuse the cultural property, detailed research about utilization and activities inside omo hada is necessary. In Law No. 11 of 2010 article 78 number 3, it is mentioned that the development of National Cultural Property is possible for improving the quality of life of the inhabitants and for preserving the cultural property. The development might add new space and function that should be harmonized with the local activities in the cultural property area. As for the appropriate use of the traditional house omo hada, modifying omo hada for new functions is possible in order to continue the living and preserve the cultural property. One idea is the homestay program, which allows the villagers to receive money for maintenance and at the same time preserve their daily life and tradition.
The homestay program keeps the basic concept of omo hada where there are three sections in a building, which are substructure, main structure and superstructure. From the sample of space layout taken in South Nias village, föröma (private space) in omo hada is often modified while tawolo (public space) remains the same. The on-site survey shows that the föröma area is often modified by changing the layout because the number of families is increasing and then some rooms are added. As a result of observing 30 houses and two sample houses, tawolo is found to be a frequently used space and it has 40% of the total space of the second floor. Therefore, it is better not to do many modifications. Meanwhile, föröma occupies 60% of the second-floor area and is used only for sleeping areas at night. Therefore, adaptive reuse can be made possible in a föröma area.
This idea of homestay came up after many foreigners and Indonesians came to Nias Island for research activity and holiday. As we see in research sample, omo hada has flexibility of the space arrangement. This adaptive reuse of omo hada allows them to continue their living culture that is mixed with modern necessities while at the same time preserving the cultural property.
Cultural Resource Studies at National Museum of Ethnology Japan for his guidance during survey and research in Bawömataluo village. Also would like to thank to Dini Aiko Subiyantoro who helped a lot during the site survey in Bawömataluo village. This work is supported by JST SPRING scholarship with Grant Number (JPMJSP2124).